Effect of Surface Passivation on Electrical Properties of Pd-F:SnO2 Thin Films Prepared by Spray Pyrolysis Technique

Abstract

Pd-F:SnO2 thin films have been prepared by spray pyrolysis technique. Optimization has been done by doping SnO2 with palladium at varying levels of concentration and then recording sheet resistance. The sheet resistivity has been observed to decrease gradually as at% Pd concentration is increased; an optimum sheet resistivity value of 2.71 × 10 −2 Ω cm has been recorded. The decrease in sheet resistivity has been attributed to presence of Pd ions which contribute in increment of charge carrier density. Using the optimum value of at% Pd doping, the same procedure has been repeated to study the effect of fluorine on Pd:SnO2; an optimum value of 1.64 × 10 Ω cm which is attributed to effects resulting from annealing the samples in nitrogen gas atmosphere.

Effect of Annealing and Surface Passivation on Doped SnO2 Thin Films Prepared by Spray Pyrolysis Technique

“…It was then added to stannic chloride solution at a concentration 2.7 at% Pd (optimum) in order make Pd: SnO 2 thin films. 1.0g of ammonium fluoride (NH 4 F) was dissolved in distilled water in order to make NH 4 F solution which was then added to the spraying solution containing stannic chloride at varying doping concentrations ranging from 0-22.74 at% F in order to make F: SnO 2 thin films [4,3,7,8].…”

“…Upon passivating the annealed thin films, the calculated band gap energy increased slightly. The increase calculated band gap energy is attributed to increase in the formation of nanocrystalline grains [33] or effects arising from annealing the thin film in an oxygen deficient atmosphere [7]. Figure 6 shows the effect of annealing and passivation on sheet resistivity of undoped SnO 2 thin films.…”

“…Most important is the thin film application in environmental monitoring through sensing of a number of gases. SnO 2 characteristics for gas sensing applications have been improved through catalytic and impurity doping with a view of improving on its sensitivity to a number of gases as well as its optoelectronic properties [2,4,7,8]. SnO 2 based thin films have been reported to suffer from sensitivity due to the presence of ambient humidity which has been overcome by resistive heating of the thin film gas sensor element [9].…”

“…To overcome this problem and to promote the adsorption of CO species by preadsorbed NO, thin films for gas sensing application are passivated by application of ultra-thin layer which prevents surface corrosion or modification of the surface states through post deposition treatment effects e.g. annealing and passivation [3,7,8,9,11,12,13,14,15,16]. In this study we propose to passivate doped SnO 2 based thin films by annealing them in a nitrogen gas atmosphere and study the effect of annealing and surface passivation on optoelectronic properties of doped SnO 2 thin films for CO 2 gas sensing applications.…”

Molar Concentration Effects on the Optical and Structural Properties of Nanostructural SnO₂ Thin Films

“…For these reasons SnO 2 was spotlighted in many numerous applications such as potential anode in lithium ion batteries [5], solar cells [6], gas sensors [7,8], varistors [9] and photocatalysis [ 10]. Various experimental techniques were adopted to fabricate SnO 2 thin films depending on kind of application such as, rf sputtering [11], sol-gel [12],pulsed laser deposition [13], successive ionic layer adsorption and reaction SILAR [14], electron beam evaporation technique [15],chemical vapor deposition [16] and spray pyrolysis [17,18]. Spray pyrolysis technique was used in this work to deposit SnO 2 thin films onto quartz substrates with different concentrations and study the effect of molarity on the structural, morphological and optical properties of nanostructure SnO 2 thin films.…”